Slit elastomer medical instrument valves are disclosed in Hillstead U.S. Pat. No. 4,895,565 and in numerous other patents. Such valves may be placed on the proximal end of a catheter sheath introducer, for example, to permit the introduction of a catheter or guidewire into the arterial system of a patient while preventing back bleeding through the proximal end of the catheter sheath introducer, even when a catheter or guidewire is present.
Such slit partition valves vary in their effectiveness. Particularly, such valves vary in the effectiveness of seal as a catheter or guidewire passes through the slit. Also, the various valves vary in the amount of frictional resistance they exhibit to the advancement of a catheter or the like through the valve.
Additionally, prior art valves have been subject to tearing of the elastomer material as a catheter is advanced through it. Coronary catheters may require advancement on the order of one hundred centimeters through the valve, with several catheters being sequentially inserted and withdrawn, which represents a substantial degree of friction, stress, and wear upon the slit elastomeric partition. Particularly, tearing can be instituted at the ends of the slit. In prior art designs, the slit ends may have to be reinforced to prevent such tearing.
In accordance with this invention, a new elastomeric partition member is provided for use in a valve such as a medical hemostasis valve. Significant improvements in both sealing of a catheter or the like passing through the partition valve, and reduction of friction encountered by such a catheter, are provided. Additionally, tearing of the partition during a catheter advancement or retraction step is a greatly reduced problem in the partition valves of this invention, even without reinforcement of the slit ends.